Session 23_BaseRate_Decision_Reason_handout

Session 23_BaseRate_Decision_Reason_handout - Numeric...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Base Rates and Decision Making Dr. Kim Vu PSY 332: Cognition 1 Session 24 Base Rates ± Consider the following question. ² I have a friend who is a professor. He likes to write poetry, is rather shy, and is small in PSY 332: Cognition 2 Dr. Kim Vu stature. Is he more likely to be a professor of __________________________________? ± Many people will say that the friend is a professor of _________________. ² Small stature, shy, poetry: stereotypical of that field PSY 332: Cognition 3 Dr. Kim Vu ± However, there are many more psychology professors than Chinese studies professors ± This is the base rate! Numeric example of the problem ± Suppose that 90% of Chinese scholars fit the stereotype and only 5% of Psychologists fit the stereotype ± Base rate: Suppose there are PSY 332: Cognition 4 Dr. Kim Vu ² __________ Chinese scholars ² __________ Psychologists Other Examples ± Advertisement ² “The new drug, XYZ , was given to patients and 70% of them showed improvement” PSY 332: Cognition 5 Dr. Kim Vu Base Rates vs. Diagnostic Information ± When do people use base rates? A study by Kahneman & Tvesrky (1973). PSY 332: Cognition 6 Dr. Kim Vu ± Group 1: ± If someone is chosen at random from a group of 70 lawyers and 30 engineers, what is his profession likely to be?
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Kahneman & Tvesrky (1973). ± Group 2: ± A panel of psychologist interviewed and administered personality tests to a group. PSY 332: Cognition 7 Dr. Kim Vu ² Description: hobbies include carpentry, sailing, and mathematical puzzles, and has little interest political and social issues ± What is his profession likely to be, a lawyer or engineer? Kahneman & Tvesrky (1973). ± Group3: ± Given the description and told that the individual is selected from a group of 70 PSY 332: Cognition 8 Dr. Kim Vu lawyers and 30 engineers. ± What is his profession likely to be? Why are Base-Rates Ignored? ± People often ignore base rate information when there is other information available ² ____________ information are used over base rates ² Sometimes information is used over PSY 332: Cognition 9 Dr. Kim Vu Sometimes _____________information is used over base rates ² Sometimes the _____________________ draws attention away from the base rate ² Thinking that ______________________________ ± Ignoring base rate information often leads to ___________________________________ Does the Base Rate Apply to me? PSY 332: Cognition 10 Dr. Kim Vu Does the Base Rate Apply to me? PSY 332: Cognition 11 Dr. Kim Vu Base Rate Neglect: Mammogram Example ± Julia, age 42, is worried about getting breast cancer PSY 332: Cognition 12 Dr. Kim Vu ± Assume that for a person of her background and age, there is only a 1% chance of getting cancer
Background image of page 2
3 Diagnostic information from mammograms Actual state PSY 332: Cognition 13 Dr. Kim Vu ± Julia’s mammogram comes back positive.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/05/2011 for the course PSY 332 taught by Professor Kuv8,maxfield during the Fall '09 term at CSU Long Beach.

Page1 / 8

Session 23_BaseRate_Decision_Reason_handout - Numeric...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online